Power-operated toothbrush



March 27, 1956 BLAIR POWER-OPERATED TOOTHBRUSH 2 Sheets-Sheet 1 Filed Aug. 24, 1953 INVENTOR. PAUL H. BLAIR ATTO RN EYS March 27, 1956 P. H. BLAIR POWER-OPERATED TOOTHBRUSH 2 Sheets-Sheet 2 Filed Aug. 24, 1953 l 'l l United States Patent POWER-OPERATED TOOTHBRUSH Paul H. Blair, Chicago, Ill.

Application August 24, 1953, Serial No. 376,069

1 Claim. (Cl. 15-23) This invention relates to improvements in power operated toothbrushes and has for its principal object to provide an improved and more sanitary device of the character described, having a toothbrush unit readily detachable from a power handle, so that different members of the same family may have individual toothbrush units for use with the same power handle.

A further object of the invention is to provide an improved construction for a device of the character described herein, wherein the power connections both in the handle and detachable brush unit are effectively sealed against ingress of liquid while in use.

Other objects and advantages of the invention will appear from time to time as the following description proceeds.

The invention may best be understood by referring to the accompanying drawings, in which:

Figure 1 is a plan view of a toothbrush made in accordance with my invention with the toothbrush unit assembled on the power handle;

Figure 2 is a side view of the device shown in Figure 1;

Figure 3 is an enlarged side view of the toothbrush unit removed from the power handle;

Figure 4 is an end view of the toothbrush unit shown in Figure 3;

Figure 5 is a detail section taken on line 55 of Figure 3;

Figure 6 is a fragmentary detail section of the brush unit similar to Figure 5, but showing one of the brush elements in position for removal from the unit;

Figure 7 is a section of the power handle with brush unit removed therefrom, said section being taken on line 7-7 of Figure 2;

Figure 8 is an enlarged detail perspective view of one of the stub shafts on the brush unit, and its drive connection with the driving shafts carried in the handle.

Referring now to details of the device shown in the drawings, the main parts comprise a brush unit indicated generally at 10, which is detachably mounted in telescopic relation on the outer end of a handle portion indicated generally at 11.

The brush unit 10 has a generally rectangular shallow bowl portion 12 at its outer end and an elongated hollow shell 13 at its inner end. The bowl 12 and shell 13 are preferably but not necessarily made of a single piece of molded plastic. The bowl 12 is so shaped as to receive frusto-conical rotary brush elements 14 and 15 in side by side partially overlapping relation on longitudinally extended parallel spindles 16 and 17, respectively. The bowl 12 is preferably of minimum size to accommodate the brush elements 14 and 15. The open face of the bowl permits relatively small portions of the peripheries of the two brush elements to project above the rim in position to engage the teeth and gums of the user as the brush elements are rotated, but the bottom, side and end walls of the bowl enclose and protect the major portions of said brush elements from contact with other parts of the users mouth. An oval hole 18 may be formed longitudinally of the under face of the bowl 12 for flushing the bowl and to hang the brush unit on a hook, if desired.

The brush unit 10 has a pair of relatively short parallel stub shafts 19 and 20 rotatably mounted in bores 21 and 22 formed in a cross partition 23 at the inner end of the bowl 13. The said bores have enlarged cylindrical bearing recesses 24 and 25 intermediate their ends. The stub shafts 19 and 20 have collars 28 and 29 fixed thereon near their outer ends which fit in the enlarged recesses 24 and 25.

Bearing sleeves 30 and 31 are disposed within said enlarged recesses, rearwardly of the collars 28 and 29. Said bearing sleeves 30 and 31 are made of any suitable resilient compressible material, such as rubber, of such dimensions as to fill the spaces between the spindles 19 and 20 and their respective enlarged recesses 24 and 25. Said bearing sleeves are also compressible endwise to permit the spindles to be pushed inwardly along their respective bores, when it is desired to remove either of the brush elements, as is best indicated in Figure 6.

The spindles 16 and 17 of brush elements 14 and 15 have reduced bearing pins 16a and 17a, respectively, at their outer ends which are normally adapted to extend in bearing engagement into sockets or eyelets 35 and 36 fixed in the outer end wall of bowl 12. The inner ends of said brush spindles have cross tongues llfib'and 17b, respectively, adapted to have interfitting and driving engagement in similarly shaped cross slots forming the outer ends of the stub shafts 19 and 20 (see Figure 8). The arrangement is such that, by applying moderate pressure on either of the brush elements 14 or 15, its respective spindle 19 or 20 may be pushed in to compress its resilient bearing sleeve endwise (as for instance, the bearing sleeve 30 in Figure 6), so as to free the outer end of the brush spindle from bearing engagement within the bowl and permit said brush element to be removed from the latter for cleaning or replacement. Either of the brush elements can be replaced in the bowl by compressing their respective bearing sleeves in the same manner. It will be understood, however, that at all times the resilient bearing sleeves 30 and 31 provide effective seals against leakage of liquid from the bowl into the hollow extension 12 of the brush unit.

Referring now to the handle portion 11, said handle may also be made of molded plastic material, with an enlarged hollow rear end portion 40 enclosed by a suitable end plug 41 having an aperture 42. A flexible shaft 43 of any conventional form, adapted to be driven from a remotely disposed motor (not shown), is inserted through aperture 42 and live socket element 44 at its end is adapted for connection in any conventional manner to a drive shaft 45 suitably journalled within the enlarged handle portion 40. ln the form shown, the shaft 45 is supported in a pair of antifriction bearings 46 and 47 mounted on transverse partitions 48 and 49, within said enlarged handle portion. The drive shaft 45 has geared connections through spur gears 50 and 51 with a second drive shaft 52 in the handle. The two drive shafts 45 and 52 extend forwardly in parallel relation through a hollow extension 53 of the handle. Said extension is of substantially reduced cross sectional area, and of such size as to receive the hollow shell 13 of the brush unit 10 in telescopic fitting relation thereon. The front end of the reduced handle portion 53 is closed by a partition 54 having bores 55 and 56 within which enlarged collars 45a and 52a on the outer ends of drive shafts 45 and 52 have bearing engagement. Each of the collars 45a and 52:: are

provided with end sockets 57 and 58 within which cross tongues 59 and 69 of the stub shafts 19 and 20 are adapted to have endwise fitting engagement when the brush unit is in fully assembled relation on the handle, as shown in Figures 1 and 2.

In the form shown herein, the rear end of the brush unit is provided with a terminal flange 64 while the front end of the enlarged handle portion 40 has a similarly shaped flange 65. Suitable means are provided for securing the brush unit in assembled relation on the handle extension 53, in the formv shown, such means consisting of a pair of flexible clips 67 mounted on opposite sides of flange 65 in position to snap over the flange 64 of the brush unit when the parts are assembled.

In practice, I find it preferable to make the toothbrush element 10 including the bowl 12 and the elongated shell 13 at least as long as vbut not greatly exceeding one-half the width of the average adult jaw, so that the brush unit can be-proiected into the mouth to reach the upper and lower rear molars at either side of the mouth for engagement by the rotating brushes without projecting any part of the enlarged handle portion 40 or flanges 64 or 65, into the mouth. This affords a desirable sanitary precaution when the same handle may be used by several persons, but with individual brush units.

Although I have shown and described certain embodiments of my invention, it will be understood that I do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claim.

I claim:

In a rotary toothbrush, an enclosed hollow handle having a drive shaft journalled therein, a detachable toothbrush unit having a hollow shell telescopically mounted on one end of said handle, with a stub shaft rotatably mounted and wholly supported therein and adapted for axially interfitting relation with said drive shaft when said tooth brush unit is assembled on said handle, said toothbrush unit having a hollow end portion open to one side thereof and with a bearing socket in its outer end, a rotatable brush spindle adapted to be removably mounted in said hollow end portion with the outer end of said spindle being insertable in said bearing socket and the inner end of said spindle having means for axial interfitting and driving engagement with the outer end of the stub shaft in said toothbrush unit, and rotatable mountings for said shaft in said toothbrush unit, including an endwise resilient bushing surrounding said stub shaft and in engagement with means on said shaft to resiliently hold said shaft in axial interfitting and driving engagement with said spindle, said bushing permitting the brush spindle to be removed from, or replaced in the hollow end portion of said toothbrush unit upon longitudinal movement of said spindle,,said resilient bushing also providing a liquid seal for said stub shaft in said toothbrush unit.

References Cited in the file of this patent UNITED STATES PATENTS Schlegel Jan. 29, 1952 

